Bridge dynamic response analysis considering the spatial dependency of uncertainty parameters

Uncertain parameters with spatial dependency exist in actual bridges inevitably, which significantly affect the bridge dynamic response. However, such spatial dependency is often neglected when investigating its influence on bridge response. This study proposes a bridge dynamic response analysis method considering the spatial dependency of uncertain parameters. Firstly, the bridge uncertain parameter is described by a non-probabilistic interval field model, and the spatial dependency between adjacent values of the interval field is quantified by the Karhunen-Loève like expansion. Thus the bridge is transformed into a system with multidimensional interval parameters by finite element method. Then, the system with multidimensional interval parameters is decomposed into several one-dimensional subsystems with only one interval parameter. Finally, the interval parameters of each one-dimensional system are divided into several subintervals with small uncertainties, and the dynamic response is obtained by combining analysis of subinterval results. Numerical examples are used to verify the accuracy and efficiency of the proposed method, and the results indicate that the proposed method significantly reduces the computational effort and improves the computational efficiency. Higher level of spatial dependency of the interval field, larger subinterval number, and lower uncertainty level of the non-probabilistic interval field leads to higher dynamic analysis accuracy.